$(11\%)$ Problem $9$: Referring to the image to the right, the mass of block is m$\_\{1\}$ while the mass of block $2$ is m$\_\{2\}$ The coefficient of friction between m$\_\{1\}$ and the inclined surface is $.$ The inclined surface is at an $$ angle above the horizontal. Write an equation for the magnitude of this system's acceleration. Use the variables from the problem statement together with $g$ for acceleration from gravity in order to write your equation?